Cellular communication systems continue to grow in popularity and have become an integral part of both personal and business communications. Cellular telephones allow users to place and receive phone calls almost anywhere they travel. Moreover, as cellular telephone technology is advanced, so too has the functionality of cellular devices. For example, many cellular devices now incorporate Personal Digital Assistant (PDA) features such as calendars, address books, task lists, calculators, memo and writing programs, etc. These multi-function devices usually allow users to wirelessly send and receive electronic mail (email) messages and access the internet via a cellular network and/or a wireless local area network (WLAN), for example.
Cellular devices have radio frequency (RF) processing circuits and receive or transmit radio communications signals typically using modulation schemes. The typical cellular device may have multiple transmit and receive pathways from the antenna to a digital signal processor (DSP). In particular, each signal pathway may comprise a filter to help isolate the desired frequency band from extraneous electromagnetic signals, for example, noise and interference. Nevertheless, as frequency bands change because of regulatory reasons, expansion, etc. and as more transceivers are added to the cellular device, the likelihood of self-interference may increase.
The routing of the pathways from the antenna to the DSP in a fourth generation Long Term Evolution (LTE) device may be problematic, particularly, the RF performance demands in carrier aggregation mode. Referring to FIG. 1, an approach to a receiver device 90 is shown. The receiver device 90 illustratively includes an LTE transceiver 95 comprising a plurality of primary and secondary receivers 96a-96c, 97a-97c. The receiver device 90 illustratively includes a plurality of band pass duplexers 91a-91d for passing the respective bands of the LTE communication standard. The receiver device 90 illustratively includes a pair of double-pole, four throw switches 92a-92b coupled between the band pass duplexers 91a-91b and the LTE transceiver 95, and a pair of double-pole, double-throw switches 93a-93b coupled between the band pass duplexers 91c-91d and the LTE transceiver 95. A potential drawback of this approach is that the front end module of the receiver device 90 is complicated, which adds to difficulty and cost of manufacture. Moreover, as more band capabilities are added, the complexity also increases.